Rønnestad, M. H., Orlinsky, D., Schröder, T. A., Skovholt, T., & Willutzi, U. (2019). The professional development of counsellors and psychotherapists: Implications of empirical studies for supervision, training, and practice. Counseling & Psychotherapy Research, 19(3), 214-230.
Based on the data from two large studies, these researchers describe several pathways of psychotherapist development.